Manchurian Agent: You might at first think that given the advanced sophotechnology of the Empire and some of its peer civilizations, with appropriate technologies for mental editing, gnostic overlays, and thought-viruses, that Manchurian Agent would be something that happened an awful lot.
But no, largely because with appropriate technologies for mental auditing, this sort of thing rather stands out – even when civilians go to have a routine backup made (After all, that much change in these unusual ways? Triggers the caution-and-review alarm.), and certainly when people in sensitive positions undergo their routine audit to make sure no-one’s pulled exactly this kind of thing.
Which is not to say that there isn’t some devious mental skullduggery going on from time to time, but it has to be a heck of a lot subtler than this for the agencies responsible to get away with it.